Not Applicable
Not Applicable
The present invention relates to cutter mechanisms, and more particularly to a cutter mechanism for use in a thermal transfer printer, wherein the cutter mechanism has a cutter blade which completely disengages from a breaker bar.
There are a number of U.S. patents that disclose electronic apparatus for printing indicia on labels, some of these are restricted to hand held units and others that disclose tabletop units. Hand held labeling machines are disclosed, for example, in U.S. Pat. No. 4,264,396, Stewart; U.S. Pat. No. 4,407,692, Torbeck; U.S. Pat. No. 4,473,426, Goodwin et al.; U.S. Pat. No. 4,477,305, Hamisch; U.S. Pat. No. 4,490,206, Makely; U.S. Pat. No. 4,497,683, Hamisch; U.S. Pat. No. 4,498,947, Hamisch et al.; U.S. Pat. No. 4,511,422, Hamisch et al.; U.S. Pat. No. 4,544,434, Mistyurik; U.S. Pat. No. 4,556,442, Torbeck; U.S. Pat. No. 4,561,048, Hamisch et al.; and U.S. Pat. No. 4,680,078, Vanderpool et al. Tabletop units for this general purpose, some of which are portable are described in U.S. Pat. No. 4,440,248, Teraoka; U.S. Pat. No. 4,501,224, Shibayama; U.S. Pat. No. 4,630,538, Cushing; and U.S. Pat. No. 4,655,129, Wirth et al.
The electronic machines for printing labels of the type disclosed above all include the same general combination of elements, a print head, means for feeding labeling media to be printed past the print head, a microprocessor, a read only memory programmed with appropriate instructions to operate the microprocessor, a random access memory, a keyboard with letter, number, and function keys for the entry of alphanumeric information and instructions concerning the indicia to be printed, and a visual display such as a LED, LCD unit to assist the operator in using the machine. In a hand held printer, these components may all be enclosed in a single housing.
The labeling media comprises a series of labels that are attached to a carrier strip. The carrier strip is fed through the printer and legends are printed on the labels. The labels are then removed from the carrier and attached to the objects needing identification. As there are many types of label applications, there are many combinations of labels and carrier strips that provide labels of varying sizes, colors and formats.
A particular type of print head employs thermal transfer printing technology. Thermal transfer printing uses a heat generating print head to transfer a pigment, such as wax, carbon black, or the like, from a thermal transfer ribbon to a labeling media. By using digital technology, characters are formed by energizing a sequence of pixels on the print head which in turn melt the wax or other pigment on the ribbon transferring the image to the labeling media.
Many prior art printers have various means and methods for separating printed labeling media from the unprinted labeling media. For example, U.S. Pat. No. 4,844,629, Hoyt, discloses a slot having a serrated edge that is used to tear the labeling media. A more complicated cutting mechanism, as disclosed in U.S. Pat. No. 5,078,523, McGourty et al, is composed of opposing cutting blades. In U.S. Pat. No. 5,078,523, an electric motor pivotally moves one blade across a fixed opposing blade to cut the labeling media.
In many cutter mechanisms having a cutter blade which engages a breaker bar, such as disclosed in U.S. Pat. No. 6,113,293, the cutter blade and breaker bar remain engaged to maintain a preload needed for consistent cutting. Advantageously, maintaining the cutter blade in engagement with the breaker bar also eliminates the possibility of the blade jamming into the breaker bar and allows a constant pressure to be maintained on the breaker bar by the blade. At least one lateral edge of the cutter blade is often extended to maintain the constant engagement and eliminate the possibility of the blade jamming into the breaker bar. Unfortunately, this extended edge increases the overall width of the cutter mechanism, and thus the cost. A need exists for a cutter mechanism suitable for use in a hand held printer which has a reduced overall width while minimizing the possibility of the cutter blade jamming into the breaker bar and which is capable of maintaining sufficient pressure against the breaker bar to efficiently cut labeling media.
The present invention provides a cutter mechanism for use in a printer. The cutter mechanism includes a base and a cutter blade slidably fixed relative to the base. The cutter blade is movable along a cutting path in a first direction between a retracted position and a forward position through a cutting position. A breaker bar is fixed relative to the cutter blade, and is spaced from the cutter blade when the cutter blade is in the retracted position to define a web path between the breaker bar and the base. A first biasing member urges the blade in a second direction away from the breaker bar to completely disengage the blade from the breaker bar. The second direction is not parallel to the first direction.
A general objective of the present invention is to minimize the cutter width. This objective is accomplished by completely disengaging the cutter blade from the breaker bar when the cutter blade is in the retracted position.
Another objective of the present invention is to guide the cutter blade such that the cuter blade does not jam into the breaker bar while maintaining sufficient pressure against the breaker bar to efficiently cut labeling media. This objective is accomplished by urging the cutter blade away from the breaker bar until the blade overlaps the breaker bar.
The foregoing and other objectives and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims herein for interpreting the scope of the invention.